diff --git a/java/geocoder/src/com/google/i18n/phonenumbers/PhoneNumberToTimeZonesMapper.java b/java/geocoder/src/com/google/i18n/phonenumbers/PhoneNumberToTimeZonesMapper.java
index afbc0b2..1d01a4c 100644
--- a/java/geocoder/src/com/google/i18n/phonenumbers/PhoneNumberToTimeZonesMapper.java
+++ b/java/geocoder/src/com/google/i18n/phonenumbers/PhoneNumberToTimeZonesMapper.java
@@ -173,7 +173,7 @@ public class PhoneNumberToTimeZonesMapper {
    */
   private List<String> getTimeZonesForGeocodableNumber(PhoneNumber number) {
     List<String> timezones = prefixTimeZonesMap.lookupTimeZonesForNumber(number);
-    return Collections.unmodifiableList(timezones.isEmpty() ? UNKNOWN_TIME_ZONE_LIST
+    return Collections.unmodifiableList(timezones.size() == 0 ? UNKNOWN_TIME_ZONE_LIST
                                                             : timezones);
   }
 
@@ -186,7 +186,7 @@ public class PhoneNumberToTimeZonesMapper {
    */
   private List<String> getCountryLevelTimeZonesforNumber(PhoneNumber number) {
     List<String> timezones = prefixTimeZonesMap.lookupCountryLevelTimeZonesForNumber(number);
-    return Collections.unmodifiableList(timezones.isEmpty() ? UNKNOWN_TIME_ZONE_LIST
+    return Collections.unmodifiableList(timezones.size() == 0 ? UNKNOWN_TIME_ZONE_LIST
                                                             : timezones);
   }
 }
diff --git a/java/libphonenumber/test/com/google/i18n/phonenumbers/PhoneNumberUtilTest.java b/java/libphonenumber/test/com/google/i18n/phonenumbers/PhoneNumberUtilTest.java
index 30d26cd..1466440 100644
--- a/java/libphonenumber/test/com/google/i18n/phonenumbers/PhoneNumberUtilTest.java
+++ b/java/libphonenumber/test/com/google/i18n/phonenumbers/PhoneNumberUtilTest.java
@@ -1229,7 +1229,7 @@ public class PhoneNumberUtilTest extends TestMetadataTestCase {
     assertTrue(phoneUtil.getRegionCodesForCountryCode(49).contains(RegionCode.DE));
     assertTrue(phoneUtil.getRegionCodesForCountryCode(800).contains(RegionCode.UN001));
     // Test with invalid country calling code.
-    assertTrue(phoneUtil.getRegionCodesForCountryCode(-1).isEmpty());
+    assertTrue(phoneUtil.getRegionCodesForCountryCode(-1).size() == 0);
   }
 
   public void testGetCountryCodeForRegion() {